In recent years, great advances have been made in the area of onboard information services for mobile vehicles. Among these services are some that supply the driver of the vehicle with information pertaining to the current driving route. Services exist that calculate a route from the current position to a requested destination. Other services exist that allow one to predefine certain regularly used routes and to then download route information to the car when it is requested. These services, when queried for route information, are capable of supplying an alternate route based upon traffic obstructions—such as accidents or delays due to construction—that exist when the route is requested.
Situations regularly occur, however, in which traffic obstructions arise after route information has been delivered to the vehicle. If the route information service is not re-queried, the driver of the vehicle may remain unaware of the new obstruction. It would be desirable to provide a mobile vehicle with the ability to acquire information regarding updated traffic information.
Information services are currently broadcast in some markets using Radio Data Service (RDS) over Frequency Modulated (FM) radio. Services supplied in this manner may be referred to as FM/RDS services. FM/RDS services use a subcarrier band on Frequency Modulated (FM) transmissions to deliver data. These data may provide a text display of an FM station's name or program details, may provide a table of frequencies to the radio receiver for each station so that car radios can automatically re-tune to the strongest signal, and may also alert the driver to traffic problem reports. One limitation presented through the use of FM/RDS is the relatively narrow broadcast range of standard FM transmissions.
Satellite broadcasts may also contain data on a subcarrier band, and are not subject to the same range limitations presented by standard FM transmissions. The wide range of coverage achieved by satellites presents separate challenges in regards to broadcasting information such as traffic obstruction reports. The vast amount of data required to transmit all obstruction information within the satellite's broadcast area is prohibitive to such an attempt when one considers the finite and limited capacity available via the subcarrier band.
It would be desirable to provide a mobile vehicle with the ability to efficiently process the relevancy of traffic information, this information having been broadcast efficiently using available satellite bandwidth. It would also be desirable to then provide the driver of vehicle with the relevant information and allow the driver to request a more efficient route to the destination.